<template>
  <div
    class="magnifier-box"
    :class="vertical ? 'vertical' : ''"
    :ref="id"
    @mousemove="mousemove"
    @mouseover="mouseover"
    @mouseleave="mouseleave"
  >
    <img v-show="showImg" :src="imgUrl" alt="" />
    <div class="mouse-cover"></div>
     <div class="mouse-canvas"></div>
    <div class="edit-wrap" v-if="showEidt">
      <span class="rotate-left" @click="rotate('left')"></span>
      <span class="rotate-right" @click="rotate('right')"></span>
    </div>
  </div>
</template>

<script>
export default {
  props: {
    scale: {
      type: Number,
      default: 2.5,
    },
    url: {
      type: String,
      required: true,
    },
    bigUrl: {
      type: String,
      default: null,
    },
    scroll: {
      type: Boolean,
      default: false,
    },
    showEidt: {
      type: Boolean,
      default: false,
    },
  },
  data() {
    return {
      id: null,
      cover: null,
      imgbox: null,
      imgwrap: null,
      orginUrl: null,
      bigImgUrl: null,
      bigOrginUrl: null,
      imgUrl: null,
      img: null,
      canvas: null,
      ctx: null,
      rectTimesX: 0,
      rectTimesY: 0,
      imgTimesX: 0,
      imgTimesY: 0,
      init: false,
      step: 0,
      bigStep: 0,
      vertical: false,
      showImg: true,
    };
  },
  created() {
    var $chars =
      "ABCDEFGHJKMNPQRSTWXYZabcdefhijkmnprstwxyz2345678"; /****默认去掉了容易混淆的字符oOLl,9gq,Vv,Uu,I1****/
    var maxPos = $chars.length;
    var str = "";
    for (let i = 0; i < 10; i++) {
      str += $chars.charAt(Math.floor(Math.random() * maxPos));
    }
    this.id = str;
    this.imgUrl = this.url;
    this.orginUrl = this.url;
    this.bigImgUrl = this.bigUrl;
    this.bigOrginUrl = this.bigUrl;
  },
  watch: {
    url: function (val) {
      this.imgUrl = val;
      this.orginUrl = val;
      this.initTime();
    },
    bigUrl: function () {
      this.bigImgUrl = bigUrl;
      this.bigOrginUrl = bigUrl;
      this.initTime();
    },
  },
  mounted() {
    this.$nextTick(() => {
      this.initTime();
    });
  },
  methods: {
    initTime() {
      this.init = false;
      let box = this.$refs[this.id];
      this.imgbox = box;
      this.cover = box.querySelector(".mouse-cover");
      this.cover.style.width = this.imgbox.offsetWidth / this.scale + "px";
      this.cover.style.height = this.imgbox.offsetHeight / this.scale + "px";
      this.cover.style.left = "-100%";
      this.cover.style.top = "-100%";
      this.imgwrap = box.querySelector("img");
      let imgsrc;
      if (this.bigImgUrl) {
        imgsrc = this.bigImgUrl;
      } else {
        imgsrc = this.imgUrl;
      }

      this.img = new Image();
      this.img.src = imgsrc;
      this.img.onload = () => {
        (this.rectTimesX =
          this.imgbox.offsetWidth / this.scale / this.imgwrap.offsetWidth),
          (this.rectTimesY =
            this.imgbox.offsetHeight / this.scale / this.imgwrap.offsetHeight);
        (this.imgTimesX = this.img.width / this.imgwrap.offsetWidth),
          (this.imgTimesY = this.img.height / this.imgwrap.offsetHeight);
        this.vertical = this.img.width < this.img.height;
        this.init = true;
      };
      if (this.canvas) {
        this.canvas.parentNode.removeChild(this.canvas);
        this.canvas = null;
      }
      this.canvas = document.createElement("canvas");
      this.canvas.className = "mouse-cover-canvas";
      this.canvas.style.position = "absolute";
      this.canvas.style.left =
        this.imgbox.offsetLeft + this.imgbox.offsetWidth + 10 + "px";
      this.canvas.style.top = this.imgbox.offsetTop + "px";
      this.canvas.style.border = "1px solid #eee";
      this.canvas.style.zIndex = "99999";
      this.canvas.height = this.imgbox.offsetHeight;
      this.canvas.width = this.imgbox.offsetWidth;
      this.canvas.style.display = "none";
      //document.body.append(this.canvas);
       document.querySelector(".mouse-canvas").append(this.canvas);
      this.ctx = this.canvas.getContext("2d");
      this.ctx.clearRect(0, 0, this.canvas.width, this.canvas.height);
    },
    initBox() {
      this.showImg = false;
      this.canvas.style.display = "none";
      let box = this.$refs[this.id];
      let imgsrc;
      if (this.bigImgUrl) {
        imgsrc = this.bigImgUrl;
      } else {
        imgsrc = this.imgUrl;
      }
      this.img = new Image();
      this.img.src = imgsrc;
      this.img.onload = () => {
        this.vertical = this.img.width < this.img.height;
        this.showImg = true;
        let thumb = box.querySelector("img");
        setTimeout(() => {
          (this.rectTimesX =
            this.imgbox.offsetWidth /
            this.scale /
            box.querySelector("img").offsetWidth),
            (this.rectTimesY =
              this.imgbox.offsetHeight /
              this.scale /
              box.querySelector("img").offsetHeight);
        }, 20);
      };
    },
    mousemove(e) {
      if (!this.init) {
        return false;
      }
      let _this = this;
      //获取实际的offset
      function offset(curEle) {
        var totalLeft = null,
          totalTop = null,
          par = curEle.offsetParent;
        //首先加自己本身的左偏移和上偏移
        totalLeft += curEle.offsetLeft;
        totalTop += curEle.offsetTop;
        //只要没有找到body，我们就把父级参照物的边框和偏移也进行累加
        while (par) {
          if (navigator.userAgent.indexOf("MSIE 8.0") === -1) {
            //累加父级参照物的边框
            totalLeft += par.clientLeft;
            totalTop += par.clientTop;
          }

          //累加父级参照物本身的偏移
          totalLeft += par.offsetLeft;
          totalTop += par.offsetTop;
          par = par.offsetParent;
        }

        return {
          left: totalLeft,
          top: totalTop,
        };
      }

      function getXY(eve) {
        return {
          x: eve.clientX - _this.cover.offsetWidth / 2,
          y: eve.clientY - _this.cover.offsetHeight / 2,
        };
      }
      let oEvent = e || event;
      let pos = getXY(oEvent);
      let imgwrap = offset(this.imgwrap);
      let range = {
        minX: imgwrap.left,
        maxX: imgwrap.left + this.imgwrap.offsetWidth - this.cover.offsetWidth,
        minY: imgwrap.top - document.documentElement.scrollTop,
        maxY:
          imgwrap.top -
          document.documentElement.scrollTop +
          this.imgwrap.offsetHeight -
          this.cover.offsetHeight,
      };
      if (pos.x > range.maxX) {
        pos.x = range.maxX;
      }
      if (pos.x < range.minX) {
        pos.x = range.minX;
      }
      if (pos.y > range.maxY) {
        pos.y = range.maxY;
      }
      if (pos.y < range.minY) {
        pos.y = range.minY;
      }
      this.cover.style.left = pos.x + "px";
      this.cover.style.top = pos.y + "px";
      this.ctx.clearRect(
        0,
        0,
        this.imgwrap.offsetWidth,
        this.imgwrap.offsetHeight
      );
      let startX = pos.x - (imgwrap.left - document.documentElement.scrollLeft),
        startY = pos.y - (imgwrap.top - document.documentElement.scrollTop);
      this.ctx.drawImage(
        this.img,
        startX * this.imgTimesX,
        startY * this.imgTimesY,
        this.img.width * this.rectTimesX,
        this.img.height * this.rectTimesY,
        0,
        0,
        this.imgbox.offsetWidth,
        this.imgbox.offsetHeight
      );
    },
    mouseover(e) {
      console.log("鼠标经过的时候")
      if (!this.init) {
        return false;
      }
      e = e || event;
      if (!this.scroll) {
        e.currentTarget.addEventListener(
          "mousewheel",
          function (ev) {
            ev.preventDefault();
          },
          false
        );

        e.currentTarget.addEventListener(
          "DOMMouseScroll",
          function (ev) {
            ev.preventDefault();
          },
          false
        );
      }

      this.cover.style.display = "block";
      this.canvas.style.display = "block";
    },
    mouseleave() {
      if (!this.init) {
        return false;
      }
      this.cover.style.display = "none";
      this.canvas.style.display = "none";
    },
    rotate(direction) {
      var orginImg = new Image();
      orginImg.crossOrigin = "Anonymous";
      orginImg.src = this.orginUrl;
      orginImg.onload = () => {
        this.rotateImg(orginImg, direction, this.step);
      };
      if (this.bigOrginUrl) {
        var bigOrginImg = new Image();
        orginImg.crossOrigin = "Anonymous";
        bigOrginImg.src = this.bigOrginUrl;
        bigOrginImg.onload = () => {
          this.rotateImg(bigOrginImg, direction, this.bigStep, true);
        };
      }
    },
    rotateImg(img, direction, step, isBig = false) {
      var min_step = 0;
      var max_step = 3;
      if (img == null) return;
      //img的高度和宽度不能在img元素隐藏后获取，否则会出错
      var height = img.height;
      var width = img.width;
console.log(width)
      if (step == null) {
        step = min_step;
      }
      if (direction == "right") {
        step++;
        //旋转到原位置，即超过最大值
        step > max_step && (step = min_step);
      } else {
        step--;
        step < min_step && (step = max_step);
      }
      var canvas = document.createElement("canvas");

      //旋转角度以弧度值为参数
      var degree = (step * 90 * Math.PI) / 180;
      var ctx = canvas.getContext("2d");
      canvas.width = height;
      canvas.height = width;
      ctx.rotate(degree);
      ctx.drawImage(img, 0, -height);
      switch (step) {
        case 0:
          canvas.width = width;
          canvas.height = height;
          ctx.drawImage(img, 0, 0);
          break;
        case 1:
          canvas.width = height;
          canvas.height = width;
          ctx.rotate(degree);
          ctx.drawImage(img, 0, -height);
          break;
        case 2:
          canvas.width = width;
          canvas.height = height;
          ctx.rotate(degree);
          ctx.drawImage(img, -width, -height);
          break;
        case 3:
          canvas.width = height;
          canvas.height = width;
          ctx.rotate(degree);
          ctx.drawImage(img, -width, 0);
          break;
      }
      var newImg = canvas.toDataURL();

      if (isBig) {
        this.bigImgUrl = newImg;
        this.bigStep = step;
        this.initBox();
      } else {
        this.imgUrl = newImg;
        this.step = step;
        this.$nextTick(() => {
          this.initBox();
        });
      }
    },
  },
};
</script>
<style>
.magnifier-box {
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden;
  /* position: relative; */
}
.magnifier-box .vertical img {
  height: 100%;
  width: auto;
}

.mouse-cover-canvas {
  position: fixed;
  left: 100%;
  top: 0;
  width: 315px;
  height:315px;
  /* width: 20%;
  height: 50%; */
}
.mouse-cover {
  position: fixed;
  background-color: rgba(0, 0, 0, 0.5);
  cursor: move;
}
.magnifier-box img {
  width: 100%;
  height: 100%;
}
.edit-wrap {
  position: absolute;
  top: 5px;
  right: 0;
  z-index: 9999999;
  background: rgba(0, 0, 0, 0.4);
  padding: 5px 15px 0 15px;
  border-radius: 15px;
}
.rotate-left {
  display: inline-block;
  cursor: pointer;
  width: 16px;
  height: 16px;
  background: url("../assets/img/rotate.png");
  background-size: 100% 100%;
  -moz-transform: scaleX(-1);
  -webkit-transform: scaleX(-1);
  -o-transform: scaleX(-1);
  transform: scaleX(-1);
  /*IE*/
  filter: FlipH;
}
.rotate-right {
  margin-left: 10px;
  cursor: pointer;
  display: inline-block;
  width: 16px;
  height: 16px;
    background: url("../assets/img/rotate.png");
  background-size: 100% 100%;
}
</style>
